Is my '05 diff really a ticking time bomb?
Thread Starter
Drifting
Joined: Sep 2010
Posts: 1,311
Likes: 0
From: Chicago IL
Is my '05 diff really a ticking time bomb?
When I bought my 2005 A4 a few months ago, I have to be honest in that I did no real research. Specifically, I didnt know about the weak differential in '05 models. Now, after having read all the horror stories, I cant even get into my throttle anymore for fear of the diff exploding. Its a sad situation.....378 RWHP and I dont even use half of it I bet.
My question is, am I being paranoid, or is the problem really THAT bad with these? My major concern isnt just the diff itself, but the fact that it may take the tranny with it (bent shaft). Upgrading to an '06+ diff is definately on my top 3 mods list....should it be #1? At 1st, I really wanted a diff swap to get 3.73 gears, but now im thinking more along the lines as the swap being a preventitive maintinence issue now.
Finally, with an upgraded diff, and a set of sticky nittos should I be basically bullet-proof? Or do I still have a high risk of even an '06+ diff blowing with just 378 RWHP?
My question is, am I being paranoid, or is the problem really THAT bad with these? My major concern isnt just the diff itself, but the fact that it may take the tranny with it (bent shaft). Upgrading to an '06+ diff is definately on my top 3 mods list....should it be #1? At 1st, I really wanted a diff swap to get 3.73 gears, but now im thinking more along the lines as the swap being a preventitive maintinence issue now.
Finally, with an upgraded diff, and a set of sticky nittos should I be basically bullet-proof? Or do I still have a high risk of even an '06+ diff blowing with just 378 RWHP?
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
i have a 2005 with ~450 rwhp and a MN6. My diff has not broken. I try not to abuse it.
I think the stress of dropping the clutch suddenly from a dead stop or wheel hop can result in breakage. But I've had no issues (so far at least). In any case, if it breaks, it breaks. I'll just put in a new one. No use in worrying.
I think the stress of dropping the clutch suddenly from a dead stop or wheel hop can result in breakage. But I've had no issues (so far at least). In any case, if it breaks, it breaks. I'll just put in a new one. No use in worrying.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
There are several upgrade options that also increase performance by regearing the diff and using a different style case. I would consult any of the local forum tuners in your location. I would recomend one but you didnt fill out any of your bio info telling us where you are. You wont get much help if you dont fill these things out.
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 26
From: Austin Texas
Nearly all the '05 diff. problems were with the manual trans. At least 1/2 the '05's were A4's but 90%+ of the failures are the manual transmisions. The torque convertor put much less of a shock load on the differential.
Check with a Forum Vendor as to whether an A6 diff. will even bolt to an A4.
Check with a Forum Vendor as to whether an A6 diff. will even bolt to an A4.
Burning Brakes
Joined: Jun 2008
Posts: 1,214
Likes: 3
From: CA
Like the others have said, most of the diffs that broke were on manual cars, not autos. I have a buddy who had a 05 with the A4 and over 500RWHP with the stock diff. He never broke it, but then again the car spent a lot of time in the shop for tranny issues.
My advise...avoid wheelhop at all cost and start saving up for a better diff.
My advise...avoid wheelhop at all cost and start saving up for a better diff.
Burning Brakes
Joined: Oct 2006
Posts: 995
Likes: 2
From: Virginia Beach VA
Don't be paranoid.
They do break, I have seen it happen 1st hand, but they're guys like Joe G. w/ 450+hp & drag radials w/ 6spd doing 6000rpm+ launches at the drag strip who got 300 passes b/f she gave up the ghost. My car's stats are the same as his, I've made a bunch of passes at the strip, pretty much drive it like I stole it since the day I bought new in '05, and don't give it a 2nd thought. Altough there are reports of unexplained failures, by in large it's due to wheel hop under hard acceleration or dead hook launches. So if you feel wheels start to hop, get outta the throttle, & unless you put some type strip tire & do a smokey burnout & launch on a very sticky track, you'll never dead hook on street tires. If you need more for peace of mind go to YouTube, type in "Corvette Magic, now you see it, poof, now you don't.", in search for a video to see what they'll take. I've done plenty of these.
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Former Vendor
Joined: Sep 2010
Posts: 682
Likes: 11
From: Anderson Indiana
Nearly all the '05 diff. problems were with the manual trans. At least 1/2 the '05's were A4's but 90%+ of the failures are the manual transmisions. The torque convertor put much less of a shock load on the differential.
Check with a Forum Vendor as to whether an A6 diff. will even bolt to an A4.
Check with a Forum Vendor as to whether an A6 diff. will even bolt to an A4.
CF Senior Member
Joined: Feb 2006
Posts: 23,313
Likes: 25
From: Tucson Arizona
My modified 2005 MN6 puts down a fair amount of power and its been almost bulletproof. I don't do (many) high RPM launches off the line but I road race the car a lot. Considering how I use the car its been amazing. The differential has never been a problem. If you're a serious drag racer you might want to make some modifications or add the DTE strut to prevent consequential damage to the transmission if the rear end should detonate. In stock trim with 'normal' use and an automatic transmission I wouldn't be overly concerned.
